Power transmitting mechanism



June 24, 1952 B. w. KEEsE 2,601,297

POWER TRANSMITTING MECHANISM Filed Nov. 29, 1945 3 Sheets-Sheet l m JM Emw June 24, 1952 B. w. KEESE POWER TRANSMITTING MECHANISM 3 Sheets-Sheet2 Filed Nov. 29, 1945 el/er//U W /feese June 24, 1952 B. W. KEESE2,601,297l

POWER TRANSMITTING MECHANISM Filed Nov. 29, 1945 3 Sheets-Sheet 3Patented June 24, 1952 POWER TRANSMITTING MECHANISM Beverly W. Keese,Oshkosh, Wis., assignor to The Timken-Detroit Axle Company, Detroit,Mich.,

a corporation of Ohio Application November 29, 1945, Serial No. 631,636

14 Claims.

This invention relates to an improved power transfer case for motorvehicles and has for its general object and purpose to provide a noveltransfer case construction having improved means operable with ease andfacility for transmitting power from the input to the output shaft ofthe transfer case at any one of several selective driving speed ratios.

It is a more particular object of the invention to provide a transfercase having direct, overdrive and underdrive power transmission meansbetween the input and output shaft, with clutch .devices of improveddesign for establishing the selected driving speed which may be easilyand noiselessiy operated either manually or by remotely controlled fluidpressure operated means.

Another object of the invention is to provide a multispeed drive powertransfer case with power take-off means in a compactly assembled unit,together with means for driving the power take-off shaft from the powerinput shaft independently of the speed selecting clutch devices and thepower transmission gear train.

It is a further object of the invention to provide a novel mounting ofthe clutch fork shifter rods with detent means for retaining the same inshifted position and means for connecting said rods to the iiuidpressure operated means which will compensate for misalignment.

An additional object of the invention is to provide a novel clutchoperating unit associated with the power output shaft and an axle driveshaft to actuate the movable clutch member under differential pressuresto its engaged and disengaged positions respectively.

It is also the aim and purpose of my present invention to provide apower transfer case for motor vehicles as above characterized, in whichthe several cooperating elements are of simple, rugged and durablestructural forms and will einciently function with minimum maintenance.expense- With the above and other subordinate objects in view, theinvention comprises the improved power transfer case, and theconstruction and relative arrangement of the several parts thereof, aswill hereinafter be more fully described, illustrated in theaccompanying drawings and subsequently incorporated in the subjoinedclaims.

In the drawings wherein I have disclosed one simple and practicalembodiment of my present invention, and in which similar referencecharacters designate corresponding parts throughout the several views:

`Figure 1 is a vertical longitudinal section taken substantially on theline I-I of Figure 2;

Figure 2 is an elevation of one end of the transfer case;

Figure 3 is a similar View of the opposite end thereof;

Figure 4 is a fragmentary vertical section illustrating a preferredconnecting means between the fluid pressure actuated pistons and theclutch fork shifter rods;

Figure 5 is a transverse sectional view taken substantially on the line5 5 of Figure 4; and

Figure 5 is a fragmentary vertical section on an enlarged scale showingthe front axle drive shaft disconnected from the power output shaft.

Referring in further detail to the drawings, the power transfer gearingto be presently described in detail is enclosed within a suitablehousing structure, which in the present instance includes the housingbody i0 closed at one of its ends by a wall I2 and open at its otherend. This open end of the housing body is flanged and a cover member I4is detachably secured thereto by means of bolts indicated at I6.

Adjacent their upper ends, the housing wall I2 and the cover member I4are formed with the hollow bosses I8 and 20 respectively, ,receiving theanti-friction bearings 22 and 24, in which the power input shaft 2S isjournalled. This shaft at one of its ends has a reduced splinedextension 28 projecting externally of the housing and upon the same theinternally splined hub 32 of a universal joint ange 30 is engaged andheld against axial movement by means of the nut 34 threaded on the endof said shaft. The inner end of the hub 32 is engaged with a spacingwasher 36 on the shaft section 28 which bears against the inner racering of the bearing 22. The outer open end of the boss I8 is closed bymeans of the cap plate 38 secured to the housing wall by bolts 46 andcarrying a conventional lubricant seal 42 surrounding the huby 32. Themotor driven shaft is adapted to be connected to the flange 3E) in theconventional manner.

In spaced relation from the bearing 22. the shaft 26 is formed with adiametrically enlarged section 44. Between the enlarged section of theshaft and bearing 22, a wide gear member 46 is loosely mounted to rotaterelative to the shaft upon the axially spaced anti-friction bearingrollers 48 mounted in the cage rings 5i! which are held in axiallyspaced apart relation by the spacer ring 52. The gear is formed with anoil duct 5d leading from an annular cavity 56 in one side of the gear tothe space between the roller bearings 48.

A second narrow gear 58 of greater diameter than the gear 46 is alsomounted at the opposite side of the shaft enlargement 44 for rotationrelative to said shaft upon the roller bearings B0 which are similar tothose just described and to which oil is supplied through the duct 62formed in the gear. The enlargement it of the shaft 25 has formed uponits periphery two axially spaced annular series of teeth 5d, and theopposing end of each of the gears $5 and 53 is provided with a similarseries of clutch teeth 55 and 65 respectively of the same diameter asthe teeth titl. A shiftable clutch collar l is provided with internalclutch teeth E2 slidably engaged with the teeth 64 and which are adaptedto intermesh with the clutch teeth 55 and G8 when said collar is shiftedin the appropriate direction to selectively connect the gears 45 and 58with the shaft 2S for unitary rotation therewith. The collar 'It isformed with an external annular groove ffl to receive the arms of ashifting fork 75 which is fixed to a shifter rod i8 supported at itsends in the housing wall i2 and cover member Ill for axial movement aswill be later explained.

The clutch teeth on the shaft and gears and the collar 'I may be of theconstruction described in United States Letters Patent No. 2,398,407,issued April 16, 1946, so that, in the shifting of the clutch collar toengaged position the confronting end faces of the teeth thereon and onthe gear are disposed in relative sliding abutting contact in a commonsurface of revolution until a condition of substantial synchronism isreached, when the teeth on the clutch collar will then smoothly movewithout jerk or clash into full meshed engagement with the teeth on thegear.

Also, as disclosed in said patent, certain of the teeth on the clutchcollar may be provided with inclined end faces for engagement by springpressedv detents 8|] carried by the enlargement is of" the shaft 28 tourge the clutch collar to its nal fully meshed position, and free saidcollar from frictional contact with the shifting fork le. Also theclutch collar may be internally provided centrally thereof with notchedlugs B2 for engagement by the detents 8l) to hold said collar in f.

its neutral position against casual axial movement into frictionalcontact with the side faces of the arms of fork 76.

In spaced relation to the gear 58, a gear 8d of relativelyV smalldiameter is keyed to the shaft 25 as shown at S5 and held against axialmovement in one direction by means of the spacing collar S8 surroundingsaid shaft between one side of the gear and the adjacent cage ring forone of the bearings 65. At its opposite side, the gear 84 is formed withthe hub extension S5 abutting the inner race ring of bearing 24. Withthe outer side of said race ring, theinner end of a sleeve 92= securedVto shaft 26 by the key Sii is in contact. This sleeve is held againstaxial movement outwardly on the end of shaft 25 by means of the plate 96engaged with the end face of the sleeve and secured to the shaft end bymeans of bolts 98. This end of the sleeve is formed with a drive pinionI'Ilil for the power take-off device to be later described.

Below the power input shaft 25, and transversely offset from a verticalplane containing the axis of said input shaft, a countershaft |92 isjournalled at its opposite ends in anti-friction bearings Illli of thetapered roller type mounted in openings provided in the housing end wallI2 and cover member Ii. One end of this shaft is provided withspeedometer drive means |55 enclosed within the hollow cap member |58which is-securelyV boltedV to the housing wall I2. cap plate I5 boltedto the cover member I4 has a flange I|2 bearingY against the outer racering ofu the adjacent bearing |86' while the end of the inner race ringis engaged bythe retaining plate The 1 the input shaft 26.

i II!! secured to the end of shaft |52 by the bolts H6.

To a diametrically reduced section of the shaft |02, gear ||8 is fixedfor rotation therewith by means of the key |25, said gear abutting theinner race ring of the adjacent bearing |95 and being held against axialmovement thereby and by the shoulder formed by the reduced part of theshaft |62. This gear I It is in constant mesh i with the teeth of gear:t5 on the input shaft 2S.

The intermediate section of shaft |52 of the largest diameter has asmall diameter gear integrally formed therewith and in constant meshwith the teeth of the large gear 58 mounted on The shaft enlargement |22at one side of the gear |251 is provided on its periphery with teeth IZlslidably engaged by the internal teeth |25 of an axially shiftableclutch collar |23. This collar is provided with a pcripheral groove |39which receives the arms of the fork |32 xed to the fork shifting rod |34mounted in the housing end Wall l2 and cover member I4 below and inparallel relation with the shifter rod 'I8 for the clutch collar le.Upon a reduced diameter section I S6 of the countershaft a gear |38 isrotatably supported on the spaced sets of roller bearings MS which aresimilar to the above described bearings (t8 and 55 and are supplied withlubricant through the duct |42 in said gear. adjacent the clutch collarIZS with an annular series of clutch teeth I lli with which the internalteeth |25 on the collar are adapted to intermesh. These clutch teeth areof the same construction as those provided on the collar I0 and gears leand 58 and operate in the same manner to provide a smooth non-clashingintermeshing engagement between the teeth of the clutch collar |28 andgear |38. The shaft enlargement H22 carries detents indicated at I 55 toengage the inclined ends of certain of the teeth on the clutch collar tourge the same to its fully meshed position.

Below the countershaft is journalled at its opposite ends in theanti-friction bearings |55 and |52 respectively mounted in the housingwall I2 and cover member Ill. The end of the shaft which projects beyondthe bearing |52 is splined as at 55 to receive the internally splinedhub |58 of the universal joint flange |50. At its inner end the hubcontacts the inner race ringl of bearingA |52 and is held against axialoutward movement'on the shaft by means of the nut |52 threaded upon areduced end portion of the shaft. With the flange |55, the usualpropeller shaft for transmitting power to the rear drive axle of thevehicle is adapted to be connected. A cap plate or closure |54 issecured to the cover member |51 by suitable bolts indicated at |56 andis formed with a flange It extending into the bearing receiving openingin said end member in ccntact'with the outer end face of the outer racering of bearing |52. This cap member carries the lubricant seals |10engaged with the periphery of hub |58.

The other end of the outputv shaft |8 projecting beyond bearing is alsosplined as at H2 to receive the internally splined clutch member I'lrigidly fixed thereto by the set screw H5. outer end of the inner racering of bearing |53 and at its other end is formed with an annularseries of clutch teeth |78 projecting axially therefrom beyond the endface of shaft It. This end of the shaft is also formed with a coaxialcylindrical recess in which a bearing bushing |82 is4 This gear isprovided on the end` This clutch member at one end abuts thev fitted andlubricant passing through the bearing |50 is supplied thereto throughone or more radial apertures |84 opening at their outer ends into thespaces between the splines |12.

To the housing Wall 2, a casing |86 is securely bolted as at |88. thisend of the casing being formed with a flange |99 extending into theopening in the housing wall and contacting the outer end of the outerrace ring of bearing |50.

The outer end wall of the casing |86 is provided with a counterboredopening |92 to receive the anti-friction bearing |94 in which a stubshaft |96 is journalled. This shaft includes a large diameter sectionextending inwardly from the bearing |94 and externally splined as at |98with which the internally splined axially shiftable clutch collar 200 isengaged. This collar on its inner end is provided with an annular seriesof clutch teeth 202 for intermeshing engagement with the teeth |18 ofthe member |14. The confronting end faces of the two series of clutchteeth are of the same construction as those previously referred to sothat they will smoothly intermesh without jerk or clash when the clutchcollar is shifted to engaged position. This collar is also provided withan external annular groove 204 to receive the arms of the shifting fork206.

The bushing |82 in the end of shaft |48 provides a pilot bearing inwhich the diametrically reduced axial extension 208 of the splinedportion |98 of shaft |96 is journalled for free rotation relative toshaft |48.

The outer end of shaft section |98 abuts the inner race ring of bearing|94, said bearing ring being mounted upon the splined outer end section2| 8 of the stub shaft which receives the internally splined hub 2|2 ofthe universal joint flange 2 I4 with which the propeller shaft for afront vehicle drive axle is adapted to be connected. The inner end ofhub 2 2 contacts the inner ring of bearing |94 and it is held againstaxial outward movement on the shaft by nut 2|6 threaded upon the reducedend of the shaft.

A hollow cap member 2|8 is bolted as at 220 to the wall of casing |86,and at the face thereof opposed toA said wall is recessed as at 222 toreceive the outer edge portion of the outer ring of bearing |94. Capmember 2|8 is provided with the lubricant seals 224 contacting theperiphery of the hub 2|2 In the upper end of the casing |86, one end ofa fork shifter rod 226 is supported for axial sliding movement in theopening 228 in a boss 230 formed on the top and inner side wall of thecasing |86. The opposite end 232 of the rod A226 is of relatively largediameter and is slidably mounted in the bushing 234 in the outer sidewall of casing |86. To the rod 226, the fork 206 is rigidly fixed by theset screw 236 and the top wall of casing |86 is provided with an accessopening 238 normally closed by the threaded plug 240.

To the casing |86, a cylinder 242 is rigidly secured at one of its ends,said end of the cylinder having an opening 244 through which the part232 of shifter rod 226 is freely movable. This end of the shifter rodhas a threaded axial bore 246 with which the inner threaded end of therod 248 is connected. A piston 250 has a central opening receiving thethreaded end portion of rod 248 and is tightly clamped against the endface of the part 232 of shifter rod 226 by means of a collar 252threaded on the rod 248. Piston 250 has a flange 254 projecting from oneside face thereof adapted for contact with the internal surface 256 onthe end Wall of cylinder 242 to limit movement of piston 250 and rod7226 in one direction. Movement of said piston and rod in the oppositedirection is limited by contact of the studs 298 on collar 252 with theinternal surface 268 of the cylinder head 262 which closes the outer endof cylinder 242. This cylinder head is preferably provided with asuitable stuffing box indicated at 264 through which rod 248 extends.The outer end ofl said rod is provided with a fork 266 to which suitablemanually operable means, conventionally indicated at 261 is connected.

In normal operation, the clutch fori; shifting rod 226 is fluid pressureoperated. As shown, air or other fluid medium is supplied at equalpressure from a reservoir or other supply source through a control uniton the instrument panel or steering post of the vehicle to the inletports 268 and 210, respectively, in the inner end of the cylinder walland in the head 2012. When port 210 is connected with the pressuresource, the fluid pressure is admitted to the outer end of cylinder 24,2and acts against the relatively large outer surface area of the piston25|) to move the same at comparatively low speed to the position shownin Figure l, and thus shift the rod 226 to the right to engage the teethof clutch collar 286 with the teeth of the clutch member |14 therebytransmitting power from the output shaft |48 through stub shaft |96 tothe front vehicle axle. When it is not desired to drive the front axle,shaft |48 is declutched from the shaft |96 by operating the control unitto release pressure from cylinder 242 through port 210 and supplypressure fluid through the port 268. This pressure can act only againstthe relatively small annular surface area 212 of the piston 250 betweenthe flange 254 thereon and the cylinder wall. A relatively higher forcewill thus be initially applied to the piston to rapidly move the saineand the rod 226 in the left to the position shown in Figure 6, therebyovercoming torque resistance and quickly disengaging the teeth of collar208 from the clutch teeth |18 on member |14.

The clutch collar 209 and fork 208 are held in either shifted positionby means of the usual latching detent, which in this instance is in theform of a ball 214 in the inner end of a vertical bore 216 in the topwall of casing |86 which is yieldingly urged by spring 218 into seatingengagement with the longitudinally spaced concave notches or recesses280 extending transversely across the upper side of the end portion ofrod 216 mounted in the boss 230.

As will be seen from reference to Figure 3 of the drawings, the poweroutput shaft |48 is preferably mounted with its axis disposed in acommon vertical plane with the axis of the power input shaft 26. To theshaft |48 between a shoulder 282 thereon and the bearing |50 a gear 284is keyed as at 286 and is in constant mesh with the gear ||8 oncountershaft |82. It will thus be understood that the drive gearing andadjustable clutch collars 10 and |28 constitute power transfer mechanismbetween the input shaft 26 and the output shaft |48.

Upon the upper end of the cover member I4 a power take-off housing ismounted. As herein shown, this housing comprises a body section 288having a side wall provided with spaced open ings to receive threadedstuds 290 projecting from cover member I4 and upon which clamping nuts292 are threaded. This housing wall is formed with an annular boss 294extending within the opening of the member |4 containing bearing 24 andabuttingV the outer race ring of.

saidbearing. The end of sha-ft- 28, together with sleeve 92 and gear |88thereon, are received in the housing body 288 and a conventional typeginal flange on the housing section 288 by thespaced. bolts 382 and nuts384.

In: the upper end of cover 298' and the opposed sidewall of housing 288,a power take-off shaft 386 of conventional form is journalled by the4anti-friction bearings 308. Suitable connections are' provided at one.`orY both ends: of this shaft.

for operative connection with drive means forl an auxiliary machine.Upon the shaft 3.83 withinthe housing a gear 3|8f is keyed at 3|-2 andsuitably secured against axial movement thereon. The teeth 3|4 of thisgear. have flat end faces-i for sliding abutting contact with theconfronting end faces onYthe teeth 3|8 of the axially shiftable gear316' having, splined` sliding engagement with a countershaft 320 journalled at. its oppositeendsv by the anti-friction bearings 322mounted in the side wall of housingsection 288 and cover member298respectively. Y A cover plate 324 for the outer end of shaft 320 andtheassociated bearing 322 is secured tothe face of the housing cover 298 bybolts 325. Thew opening; in the wall of housing section 288 for theother endof shaft 32|)Y and associated bearing 322` is closed by acuppedor flanged cover plateA 328 ntted within said opening.

The teethof the gear |00xed to the end of input shaft 28 are of similarform and construction to the gear teeth 314 and 3|8 so that. when thegear 316 is shifted inone direction the teeth thereof willsimultaneously mesh` with the teeth of the gear |88- and gear 3|8- inthemanner above explained.

The gear member 318 isprovided with-.an annular groove 335 to receivetheY arms of a fork 332 xed to the axially shiftablerod 334 mounted atitsv ends in the housing section 288 and cover member 288. To this covermember, a cylinder and piston assembly, generally indicated at` 333,is'attached by the bolts 338i and operatively connected with one end ofthe'rod 334-. This mechanism. which is substantially identical withv theuid pressure` operated mechanism for the shiftable clutch memberiilil'betweenv the shaftsy |48- and |96, operates in a similar manner toaxially shift the gear member 3|6 on the shaft32: into and out ofintermeshed relation with theV teeth ccuntershaft 325i are located inA acommonplane disposed at an angle of substantially forty-five Vdegreeswith respect tol a horizontal. plane in.-

tersectingthe axis ofthev power input shaft 28. Thus. the powertake-olf; shaft will beconveniently located adjacenty one side of thevehicle frame. In counterbalancing relation thereto, fluid pressureoperated actuating units for the respective clutch, fork shifter rods 18and |34 are Y rigidly mounted upon the housing cover member I4, thusmore or less equally distributing stress forces upon the cover attachingbolts I8.

The` actuating unit for the shifter rod 18 includes a` cylinder 340 andpiston mechanism reciprocating therein together with an associatedpressure operated valve mechanism 342 connected with the selective;control unit on the steering.; post: or instrument panel of the vehiclefor governing theY supply of pressure fluid, to

cylinder 348 from a manifold 344 suitably connected with. areservoir orother source of fluid pressure supply.

Similarly the actuating unit for the clutch fork. shifter rod |34includes a cylinder 34B having piston mechanism reciprocating thereinand the associated valve. mechanism 348 connected with. the selectorcontrol unit to govern the supply' of pressure fluid from manifold 344to cylinder 346v with respect to the piston mechani'srn therein. As thepiston and cylinder assemblies with their associated valve mechanismsand the selector control unit are of well known construction andconstitute no essential part of the present invention, detaildescription thereof is not believed to be necessary.

Referring now to Figure 4' of. they drawing, the right hand ends of theclutch fork shifterl rods 'i8 and |34v are slidably mounted in spacedbores extendingl through an internal boss 350 formed onA the covermember I4'. The rods or stems oi thepistons operating in the respectivecylinders 340 and 348. are connectedl to rods 18 and |34 in a similarmanner. Thus the end of each fork shifter rod is provided with aconcentric cylindrical recess 352, the wall of which is internallythreaded as at 354. The piston rod or stem 358 has an annularenlargement or head 358 on its end of somewhat less diameter than therecess 352. An annular externally threaded nut 351 is of greaterinternal diameter than the piston` stem 356V and adjustably coacts withthe threads 354 to engage the inner face of the headv 358 and tightlyclamp the same against the base wall of thev recess 352'. The outer endof thisV recess is closed by washer plate 35|. It will thus be apparentthat a rigid connection betwen the work shifter rod and the piston stemmay be easily and quickly made, although said rod and stemmayl beslightly out of trueV axial alignment.

Between` the two fork shifter rods. 18 and' |34, the boss 358- cn thehousing cover member is provided withfa bore 3.59l extending radiallybetween the rod and receiving bores in said boss and communicatingtherewith. A ball detent 333` in the lower end of this bore 353 engagesin either one of" the two axially spaced' concaveV member I4, the detentballs 360 and 364 and spring 366 may be readily inserted through theopening 368 in the upper end of the boss 350, which is then closed bythe threaded plug 310.

Each fork shifter rod 18 and |34 at the left hand end thereof is forkedand connected with manually operable means conventionally illustrated`at 312 and 814, respectively.

From the foregoing description, the construction and manner of operationof the present invention will be readily understood. In Figure l of thedrawings, the clutch collars 10 and |28 are shown in their disengaged orneutral positions. Thus, rotation will not be transmitted from the powerinput shaft 26 to the output shaft |48 but as shown in this figureactuator unit 336 has been operated to shift the clutch collar and gearmember 3|6 into meshed engagement with the teeth of gears and 3|0 sothat rotation is transmitted to the power take-off shaft 306 and gearelement |38 is idly` rotated on the stationary countershaft |02.

For the direct transmission of power from the input shaft 26 throughoutput shaft |48 to the vehicle axles, the selector lever is properlypositioned to cause operation of the actuator unit 340 for the shifterrod 18, whereby clutch collar is shifted from its neutral position, asshown in Figure l, to the left and the clutch teeth thereof areintermeshed with clutch teeth 66 on the gear 46. This gear now rotatesas a unit with the shaft 26, and through the gears ||8 and 288 transmitsrotation at the same speed to the power output shaft |48.

For the overdrive transmission of power from input shaft 26 tothevehicle axles, the selector lever is positioned to cause operation ofthe unit 340 so that clutch collar 10 will be shifted to the right fromneutral position and the clutch teeth thereof engaged with clutch teeth68 on the large gear 58, thus connecting this gear to shaft 26 forunitary rotation therewith. Gear 58 being in mesh with small gear |20 oncountershaft |02 transmits rotation through gears ||8 and 284 to thepower output shaft |48 at relatively high speed. Of course, when thedirect drive connection is made, gear 58 will be idly rotated relativeto the input shaft 26 while, when the overdrive connection is made, gear48 will be rotated relative to the input shaft. By proper adjustment ofthe operators selector lever, actuator unit 340 may be operated toreturn clutch collar 10 from either of its drive positions to theneutral position where it is disengaged from clutch teeth of both gears46 and 68.

When it is desired to establish an underdrive condition, the operatorsselector lever is set to cause operation of the actuator unit 346 andaxially shift clutch collar |28 to the right from the position shown inFigure 1 and engage the clutch teeth thereof with clutch teeth |44 ongear |38, thereby connecting the gear to countershaft |02 for unitaryrotation therewith. Power will then be transmitted from the xed gear 88on input shaft 26, through gear |38, the countershaft |02 and gears ||8and 284 to power output shaft |48, at a relatively low speed. Withclutch collar 10 in the neutral position, both gears S8 and 68 will thenbe idly rotated relative to the input shaft 26.

In each of the above described driving conditions of the power transfermechanism, with clutch collar 200 in the engaged position shown inFigure 1, rotation is transmitted to the front o and rear drive axles ofthe vehicle at the same 10 speed through the driving connections withshafts |48 and |96. The transmission of driving power to the frontvehicle axle may be discontinued at any time by the admission ofpressure fluid through cylinder part 268 to exert a high pressure forceagainst piston surface 212 shifting rod 226 and fork 206 to the left andapplying a high thrust pressure force to the collar 200 to disengage theclutch teeth thereof from the clutch teeth of member |14. By the lapplication of differential pressure forces moving piston 250 inopposite directions as above explained, different axial thrust forcesare applied to the clutch collar 200 in the clutching and declutchingoperations thereof so that, in the movement of the clutch collar toengaged position, the confronting end surfaces of the clutch teeth 202and |18 will be brought into abutting sliding contact under relativelyvlight pressure while a sufficiently high dise'ngaging pressure isapplied to the clutch collar to overcome driving torque forces andquickly disengage the teeth on said collar from the teeth |18 on member|14.

When the gear member 8| 6 is in engaged position to transmit power tothe power 'take-off shaft 306 and clutch collars 10 and |28 are inneutral position, the countershaft |02 remains stationary, and the onlyrotating gear elements are gears 84 and |38. Thus excessive wear of theelements of the power transfer gear train is reduced to a minimum. Whenpower is being transmitted to the output shaft |48, member 3|6 isaxially shifted out of engagement with the gears |00 and 3| 0 so thatthe power take-off will not be operated. However, the power takeoffshaft may also be operated simultaneously with the transfer of drivingpower between the input and output shafts for the operation ofaccessories mounted on the vehicle or a machine carried by a trailervehicle.

The housing structure l0 of the transfer case is provided in one of itsside walls with an oil ller opening normally closed by a suitable plugand in the bottom wall thereof with a drainage opening normally closedby plug 382. The oil is picked up by the teeth of the power transfergear train and is distributed therefrom through various passages to theseveral shaft and gear bearing units.

In the event of failure of any one of the fluid pressureoperatedactuator units for the several clutch devices, said devices maybe operated independently of said actuator units by the manuallyoperable means connected to the clutch fork shifter rod.

From the foregoing description considered in connection with theaccompanying drawings, it is believed that the construction, manner ofoperation and several advantages of my improved power transfer case willbe readily understood. It will be seen that I have provided a simple,compact and efficiently operating mechanism for the direct, overdrive orunderdrive transmission of power from the power input shaft to thevehicle axle. I have found that the type of easy-shift clutch devicesherein described for transmitting power at the desired speed to thepower output shaft are admirably adapted for use in connection withfluid pressure operated actuator units for the shiftable clutchmembers'. Of course, in the operation'v of such units, the operator hasno feel of the engaging contact between the confronting series of clutchteeth and cannot control the movement ofthe shiftable clutch colla-r toengaging position. Therefore, when a conventional type of clutch toothconstruction is employed and Ythe clutch collar is shifted by a fluidpressure cperated unit, owing to the heavy fluid pressure applied to theclutch collar and -torque forces, Ain the initial partial intermeshingengagement between the two series of Vclutch teeth, serious damage ormutilation of the clutch teeth is likely Vto occur. This possibility isavoided in the improved easy-sh-ift type of clutch, by reason of theabutting sliding contact of the confronting end faces of the two seriesof Vclutch teeth -in a commonV plane of revolution until the rotatingspeeds of the two series of teeth are substantially 4in synchronism,when under the fiuid pressure the teeth -on the clutch collar willsmoothly move to full intermeshing engagement with the clutch kteeth onthe gear element. It -will thus be evident that the present inventionprovides `a iiuid pressure operated clutch in the transfer lcase wherebya substantially noiseless, non-clashing driving connection may beestablished between the driving and driven elements.

It will further be seen that the present invention provides a powertake-off unit with -uid pressure operated means for establishing adriving connection between the power take-off shaft vand one end lof thepower input shaft of the transfer case and which is operableindependently of the power transfer gear train between the input andoutput shafts. The fluid pressure operated clutch means for optionallyestablishing a driving connection between the Apower output shaft andthe front vehicle axle is also an important feature of the invention.

Finally, it will be appreciated that, in view of the manifold functionsand purposes of the present invention, I have provided a very compactorganization of the several parts in a transfer case of minimumdimensions and in which the cooperating elements are of rugged anddurable structural form for prolonged efficient functional operation atVcomparatively low maintenance vexlpense;

rThe invention may be embodied in other specific Vforms withoutvdeparting from the spirit or essential characteristics thereof. Thepresent embodiment is therefore to be considered iin all respects asillustrative and not restrictive, the scope of the invention beingindicated by the frappended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency ofthe claims are therefore intended to be embraced therein.

What .is claimed and desired to be secured by United v'States LettersPatent is:

l. In a power transfer case, power input and output shafts and anintermediate countershaft, direct and overdrive power transmittingconnections between the power input and output shafts, comprisingaxially spaced gears fixed to the countershaft, direct and overdrivegears rotatably mounted on the power input shaft and in constant meshwith the respective gears on the countershaft a gear fixed to the outputshaft in mesh with the countershaft. gear engaged with Asaid directdrive gear, and clutch means com prising a clutch collar rotatable withthe input shaft between ythe direct and overdrive gears 'thereon andaxially shiftable to selectively engage clutch 'means on the respectivegears and connect the same for unitary rotation -with the finput shaft.

2. In apower rtransfer case. va housing, power input and output shaftsand a countershaft mounted in the housing, direct, overdrive landunderdrive power transfer means including axially spaced gears rotatablymounted on the input shaft and a gear rotatably mounted on thecountershaft, clutch means ycomprising an axially shiftable ,collarrotatable with the input shaft between'saidspaced gears, anactuator unithaving uid pressure operated means operatively connected to said clutchcollar `to axially shift the same and selectivelyrconnect said gears tothe input shaft for unitary rotation therewith, an axially shiftableclutch collar rotatable as -a unit with the countershaft to engageclutch means on Ythe Igear on ysaid shaft and connect the same therewithfor unitary rotation, and aseoond .actuator unit having Vfluid pressureopera-ted means operatively connected to said second `clutch collar toindependently shift the lsaine to engaged and disengaged positions.

3. The power transfer case as defined in claim 2, in which said housingincludes a detachable end cover section and said clutch actuator unitsare mounted on said cover section externally -c the housing.

4. In a power transfer case, a housing, `power input and outputshaftsmounted therein, power transfer mechanism operatively connecting saidshafts, said mechanism including an axially shiftable clutch member, ashifting fork engaged therewith, an axially -movable fork rshifter vrodmounted in the housing and connected to said shifting fork, an externalactuator unit `separably mounted on one end of the housing andhaving afluid pressure yoperated piston anda Piston Vrod substantially coaxial`with said shifter :rod, .and means connecting said rods inlongitudinally rigid force transmitting relation, said vmeans havingsufficient radial clearance with one .of said rods to compensate for anysmall axial vmisalignment between said rods.

5. in a power transfer case, a housing 'having a `body section and adetachable ,cover section closing one end thereof, input land outputshafts mounted in vertically spaced relation in said housing, powertransfer mechanism .operatively connecting said shafts, said mechanismincluding independently operable vclutches each having va shiftableclutch member, a power Ytake-off unit mounted upon said cover section of:the housing and having a power take-off shaft and drive means betweensaid shaft Vand one end of the power output shaft disposed at one sideof a vertical plane which includes the axis of the input shaft, andactuator units for said shiftable clutch members mounted on the housingcover section at the opposite side of said plane. Y

6. In a power transfer case, a housing body, a cover closing one end ofsaid body, vertically spaced power input and output shafts journalled atopposite ends in said housing body and cover respectively; a powertake-off unit comprising a separatev housing detachably mounted on saidcover, a power take-off shaft journalled in said separate housing, meansfor releasablyestablishing a driving connection between said powertake-off shaft .and the .end of the Vpower input shaft journalled insaid cover includingan axially shiftable power transmitting membermounted in the power take-olf housing and an axially shiftable rodoperatively connected with said member. and an actuator unit mounted onsaid power take-off housing comprising a fluid y:presimre operatedpiston, and means directly and rigidly connecting one end of saidaxially shiftable rod to said piston.

7. In combination with a power transfer case having a housing and ashaft journalled therein, a casing enclosing one end of said shaftdetachably secured to said housing, a second shaft journalled in saidlcasing in coaxial relation with said end of the first shaft, a clutchmember fixed to one of said shafts within the casing, a coacting clutchcollar rotatable with the other of said shafts and axially shiftablerelative thereto into and out of torque .transmitting relation with saidfixed clutch member, and an actuator unit mounted on said casing, saidunit including a fiuid pressure actuated piston, a piston rod, a shifterrod connected at one end to said clutch collar, and means connected tothe other end of said shifter rod for manually actuating said clutchcollar independently of fluid pressure.

8. In a power transfer case, a housing, power input and output shaftsmounted therein, power transfer mechanism operatively connecting saidshafts, said mechanism including an axially shiftable clutch mem-ber, ashifting fork engaged therewith, an axially movable shifter rod mountedin said housing and connected to said shifting fork, an actuator unitmounted on one end of said housing and having a fluid pressure operatedpiston, a rigid force transmitting connection between said piston andone end of said fork shifter rod, and manually operable means connectedto the other end of said shifter rod to actuate the same independentlyof said actuator unit.

9. In a power transfer mechanism, parallel power input and outputshafts, a parallel `countershaft, spaced gears rotatable on said inputshaft, means for clutching either of said gears for rotation with saidinput shaft, spaced gears on said countershaft constantly meshed withsaid gears on said input shaft, one of said gears on the countershaftalso being constantly geared to said power output shaft to provide adirect drive chain from said input shaft, and further gearing and aclutch interconnecting said input shaft with said countershaft so thatsaid countershaft maybe driven from the input shaft when neither' ofsaid spaced gears on the input shaft are clutched to the input shaft.

10. In the power transfer l'mechanism defined in claim 9, a rotatablepower take-off shaft and means for selectively connecting said input andtake-off shafts for rotation together whereby the latter may be drivenfrom the input shaft when the output shaft is not being driven.

11. In the power transfer mechanism defined in claim 9, a drive shaftjournalled coaxially with said output shaft, and means for selectivelyclutching said drive shaft and output shaft for rotation together.

12. In a power transfer case, power input and output shafts and anintermediate countershaft, direct and overdrive power transmittingconnections between the power input and output shafts, comprisingaxially spaced gears fixed to the countershaft, direct and overdrivegears rotatably mounted on the power input shaft and in constant meshwith the respective gears on the countershaft, a gear fixed to theoutput shaft in mesh with the countershaft gear engaged with said directdrive gear, clutch means comprising a clutch `collar rotatable with theinput shaft between the direct and overdrive gears thereon and axiallyshiftable to selectively engage clutch means on the respective gears andconnect the same for unitary rotation with the input shaft, andunderdrive means comprising a gear xed to the input shaft, a gearrotatably mounted on the countershaft in lconstant mesh with said fixedgear on the input shaft, and independently operable clutch means toestablish a driving connection [between said rotatable gear on thecountershaft and the countershaft when said clutch collar on the inputshaft is in neutral position.

13. In combination with a power transfer case including power input andoutput shafts and a power transfer mechanism Aconnecting said shafts: anadditional shaft and bearing means journalling said shaft in coaxialrelation with one end of the powervoutput shaft, a clutch memloer fixedto the output shaft, a coacting 'clutch collar rotatable with saidadditional shaft and axially shifta'ble relative thereto into and out oftorque transmitting relation with said fixed clutch member, and anactuator unit mounted on said transfer case operatively connected tosaid clutch collar and having means for applying axial thrust forces ofdifferent magnitude to said collar for shifting said collar into and outof clutched engagement with said fixed clutch member, said actuator unitincluding a pressure operated piston having opposite areas of differentsize subject to fluid pressure when the collar is to be shifted in onedirection or the other and a clutch fork shifter rod directly connectedat one end to said piston, the disengagement force being the greater.

14. In a power transfer case, power input and output shafts and anintermediate countcrshaft, a plurality of power transmitting connectionsbetween the power input and output shafts comprising axially spacedgears of different size fixed to the countershaft, cooperating gearsrotatably mounted on the power input shaft and in constant mesh with therespective gears on the countershafta gear fixed to the output shaft inconstant mesh with one of said countershaft gears, clutch meanscomprising a clutch collar rotatable with the input shaft between thegears on said input shaft and axially shiftalble to selectively engageclutch means on the respective gears on said input shaft and connect thesame for unitary rotation with the input shaft, a gear fixed to saidinput shaft, a gear rotatably mounted on the countershaft in constantmesh with said fixed gear on the input shaft, and an independentlyoperable clutch means to establish a driving connection :between saidrotatable gear on the countershaft and the countershaft when said clutchcollar on the input shaft is in neutral position.

BEVERLY W. KEESE.

REFERENCES CITED The following references are of record :ln the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,034,778 Storey Mar. 24, 19362,131,015 Sanford et al Sept. 20, 1938 2,163,741 Weaver June 27, 19392,263,141 Peterson Nov. 18, 1941 2,341,756 Avila Feb. 15|, 19442,398,407 Brownyer Apr. 16, 1946 2,450,896 Kimberly Oct. 12, 1948FOREIGN PATENTS Number Country Date 501,498 Great Britain Feb. 28. 1939

